I. Field of the Invention
The present invention relates generally to vehicles for collecting, transporting and unloading several sorted classes of materials, that may include recyclable materials, in which the truck body is in the form of a generally hollow container mounted on a truck chassis and having an internal volume split or compartmentalized into two or more compartments, each equipped to receive, store and discharge or eject materials separately. More particularly, the present invention relates to a split tailgate system that enables the separate operation of a tailgate door for each compartment, but which maintains a reduced center of gravity with reference to the vehicle regardless of the position of the doors.
II. Related Art
The art of refuse collection is becoming increasingly complex, particularly in view of the rising interest in requirements with respect to recyclable goods. Rules and requirements of recycling restrict comingling of unlike materials such as paper with glass, metal and plastic goods. These separately loaded and stored materials must also be kept apart during the discharge operation so that each associated compartment must be capable of being unloaded to the exclusion of others.
Vehicles of the class have been specifically designed with refuse bodies arranged in several compartments for the separate processing of segregated materials. This includes the use of a split compartment charging hopper for separately charging upper and lower storage compartments. The refuse body may employ a single set of packing cylinders in conjunction with connecting arms between upper and lower packers to operate both packers or use individual dedicated compacting mechanisms. Provision is made for separate discharge from the upper and lower compartments. Examples of these are shown and described in U.S. Pat. No, 5,868,543 which illustrates a packing apparatus with a multi-compartment storage body which includes a charging hopper divided into upper and lower portions, each having its own packing system. Front loading systems of the class are shown in U.S. Pat. Nos. 5,681,140 and 5,797,715; all of which are assigned to the same assignee as the present application.
A further tailgate design for a multiple compartment rear discharge collection vehicle is shown in U.S. Pat. No. 5,527,098 which allows access to each of two (upper and lower) compartments in a rear discharging refuse body using a plurality of doors which allows separate operation. However, both doors are hinged at the top of the refuse body. The opening of the doors at once owing to the top hinging of both doors may, in certain instances, raise the center of gravity of the system sufficiently to adversely affect the stability of the vehicle. This is particularly true in the case of a dump body unloading system in which the front of the container is raised during the discharge operation and/or wherever heavy material is loaded into the upper compartment.
It will readily be seen that a definite need remains for a rear discharging, multiple compartment refuse vehicle of the class that enables clear separate discharge of stacked compartments with a minimal effect on the center of gravity of a discharging vehicle.
The present invention provides a tailgate system for a split body collection vehicle which allows the separate discharge of upper and lower longitudinally oriented compartments in the storage container by the provision of upper and lower discharge doors featuring a vertically pivoting lower door which operates using a mid-body hinging system and is shorter than the height of the lower compartment and thereby introduces a vertical unsealed gap between the doors. An auxiliary closure device is provided to normally close the upper portion of the lower compartment maintained by the upper portion of the lower door. This unique construction provides adequate clearance that enables the lower door to open fully while the upper discharge door remains closed. Conversely, the system also enables the upper door to open alone fully or both to open at once, if desired, each mutually clearing the other without sacrificing the ability to fully expose the related compartment to allow full ejection or requiring top hinging of the lower door.
In the detailed embodiment, each of the doors is operated by a pair of oppositely disposed fluid cylinders with associated rods which, upon extension, lift and pivot the doors in a manner that accomplishes both unlatching and opening using vertically adjustable hinge pins that are designed to travel as followers along slots provided. The auxiliary closure device is an intermediate vertically pivoting plate member suspended at the top of the lower compartment and, as stated, the lower portion of the plate is normally held closed by the upper portion of the lower door when the door is in the closed position, but is allowed to freely pivot with the lower door to expose the full discharge opening of the lower compartment when the lower door is open and thereby to enable sufficient separation such that full open/close independence is achieved by the stacked doors of the tailgate system.
While the detailed description pertains to a particular embodiment of the invention, it will be appreciated that that embodiment is offered by way of example rather than limitation with respect to the underlying invention and those skilled in the art will appreciate that other embodiments could be used as well.